Upgrade Ruby 2.0.0 to patchlevel 451

Results of 'make check':

https://gist.github.com/luislavena/9201327
Update History for release
Upgrade libyaml to version 0.1.6
Add mingw64 4.8.2-rev0 x86 and x64 support
Only add DLDFLAGS for relevant DevKit's

Current GCC 4.8.x compilers add an implicit dependency to the libgcc
support library to msvcrt-rubyXYZ.dll. This overly complicates
installs and creates additional support concerns. Adding -static-libgcc
to configure's DLDFLAGS "fixes" this GCC behavior. Rather than
hard-coding DLDFLAGS for every build, set only when appropriate.

NOTE: while generic to 4.8.x, the DevKit version matching regex must
be updated to support future GCC versions if this GCC behavior persists.
Upgrade mingw64-{32,64}-4.8.2 to rev 1
Support mingw64-{32,64}-4.8.2 in Ruby20/Ruby21
Update mingw64-{32,64}-4.8.2 to rev2
Update mingw64-{32,64}-4.8.2 to rev3