Rename PythonInstalled to PythonDependency.

Make it more consistent with other requirements.

Library/Homebrew/cmd/audit.rb

@@ -568,8 +568,8 @@ class FormulaAuditor
       end
     end
 
-    unless f.requirements.any?{ |r| r.kind_of?(PythonInstalled) }
-      # So if there is no PythonInstalled requirement, we can check if the
+    unless f.requirements.any?{ |r| r.kind_of?(PythonDependency) }
+      # So if there is no PythonDependency requirement, we can check if the
       # formula still uses python and should add a `depends_on :python`
       unless f.name.to_s =~ /(pypy[0-9]*)|(python[0-9]*)/
         if text =~ /system.["' ]?python([0-9"'])?/

Library/Homebrew/dependency_collector.rb

@@ -74,7 +74,7 @@ class DependencyCollector
     elsif (tag = tags.first) && LANGUAGE_MODULES.include?(tag)
       # Next line only for legacy support of `depends_on 'module' => :python`
       # It should be replaced by `depends_on :python => 'module'`
-      return PythonInstalled.new("2", spec) if tag == :python
+      return PythonDependency.new("2", spec) if tag == :python
       LanguageModuleDependency.new(tag, spec)
     else
       Dependency.new(spec, tags)
@@ -103,8 +103,8 @@ class DependencyCollector
     when :clt        then CLTDependency.new(tags)
     when :arch       then ArchRequirement.new(tags)
     when :hg         then MercurialDependency.new(tags)
-    when :python, :python2 then PythonInstalled.new("2", tags)
-    when :python3    then PythonInstalled.new("3", tags)
+    when :python, :python2 then PythonDependency.new("2", tags)
+    when :python3    then PythonDependency.new("3", tags)
     # Tiger's ld is too old to properly link some software
     when :ld64       then LD64Dependency.new if MacOS.version < :leopard
     else

Library/Homebrew/python_helper.rb

@@ -3,7 +3,7 @@
 
 # This method has a dual nature. For one, it takes a &block and sets up
 # the ENV such that a Python, as defined in the requirements, is the default.
-# If there are multiple `PythonInstalled` requirements, the block is evaluated
+# If there are multiple `PythonDependency` requirements, the block is evaluated
 # once for each Python. This makes it possible to easily support 2.x and
 # 3.x Python bindings without code duplication in formulae.
 # If you need to special case stuff, set :allowed_major_versions.
@@ -24,8 +24,8 @@ def python_helper(options={:allowed_major_versions => [2, 3]}, &block)
     end
   end
 
-  # Look for PythonInstalled requirements for this formula:
-  python_reqs = requirements.select{ |r| r.kind_of?(PythonInstalled) }
+  # Look for PythonDependency requirements for this formula:
+  python_reqs = requirements.select{ |r| r.kind_of?(PythonDependency) }
   if python_reqs.empty?
     raise "If you use python in the formula, you have to add `depends_on :python` (or :python3)!"
   end

Library/Homebrew/requirements/python_dependency.rb

@@ -6,14 +6,14 @@ require 'requirement'
 # In `dependency_collector.rb`, special `:python` and `:python3` shortcuts are
 # defined. You can specify a minimum version of the Python that needs to be
 # present, but since not every package is ported to 3.x yet,
-# `PythonInstalled("2")` is not satisfied by 3.x.
+# `PythonDependency("2")` is not satisfied by 3.x.
 # In a formula that shall provide support for 2.x and 3.x, the idiom is:
 # depends_on :python
 # depends_on :python3 => :optional # or :recommended
 #
 # Todo:
 # - Allow further options that choose: universal, framework?, brewed?...
-class PythonInstalled < Requirement
+class PythonDependency < Requirement
   attr_reader :min_version
   attr_reader :if3then3
   attr_reader :imports