Add support for cross compiling a multi platform (x64-mingw32 and x86-mingw32) fat binary gem and support for native builds on Windows.

This moves all MiniPortile recipes into extconf.rb. This enables
native build on Windows and ensures that all depending libraries
are build with the same compiler version as the C-ext when cross compiling.
Use 'host' as alternative, because host_alias is not set on RubyInstaller-1.9.3
Remove libxslt patches that modify configure.in.

Modifications to configure.in trigger a re-run of autotools,
which adds additional dependencies to nokogiri. This breaks the build
of libxslt when there is a version mismatch between the one used to
release the libxslt tar file and the installed one.

The removed patches itself are IMHO not necessary for nokogiri.
Add missing files to Manifest.txt
Update rake-compiler version to 0.9.2 in order to avoid 'win32/resolv' error.
Move gem post install message into cross compiling callback, so that it
is really used for the packaged fat binary gems.

Avoid adding dependency.yml twice - once per Manifest.txt and once
per add_file_to_gem.
Don't trigger gem task twice in 'rake gem:windows'.

It was called as prerequisites and is called as part of
'rake cross native gem'
Use a better fix for the character escaping bug in MSYS
Merge branch 'mingw32-support' of https://github.com/larskanis/nokogiri into larskanis-mingw32-support
Clear cached nodes when relinking namespaces
Remove attribute namespace when it matches the host element's namespace
Clear cached XPathContext after attribute change or node removal
Fix incorrect namespace comparison to use attribute prefix instead of element prefix
Resolves Java extension compilation problem on OSX

The changes introduced by 2e2b204804108c5c53284bb48cf6c06ac553d120
has an incompatibiliy with Java on OSX. This makes unable to compile
Java extension on OSX.
From the source code, the second argument of JAXPExtensionsProvider
constructor is false by default and we don't need it.
Luckily, a single argument constructor of JAXPExtensionsProvider
exists on OSX Java. This change eliminates the second argument.

Also, source/target version to 1.6 are added to rake compiler.
Merge branch 'issue-1034-attr-namespaces-in-cloned-docs' of github.com:mbklein/nokogiri into mbklein-issue-1034-attr-namespaces-in-cloned-docs
Merge branch 'jruby-incorrect-xpath-caching' of github.com:mbklein/nokogiri into mbklein-jruby-incorrect-xpath-caching
Moves clearXpathContext method to NokogiriHelpers
Merge branch 'jruby-fix-xml-prefix-on-attrs' of github.com:mbklein/nokogiri into mbklein-jruby-fix-xml-prefix-on-attrs

Conflicts:
	ext/java/nokogiri/XmlNode.java
Bump VERSION to v1.6.2.beta.2.
Workaround the MSYS character escaping bug on native mingw builds only.

It was triggered on cross builds only before, so that native builds with the DevKit didn't work.
Merge pull request #1061 from larskanis/fix-msys-escape-workaround

Workaround the MSYS character escaping bug on native mingw builds only.