ruby186: fix compilation against newer OpenSSL

Fixes #258.
ruby182: fix compilation with newer OpenSSL

This is the same fix as ruby186; see #258.
ruby182: remove inaccurate caveats

Ruby 1.8.2 didn't come with rubygems.
gcc*: skip C++ stdlib checking.

* GCC boostraps itself, so it is OK to have incompatible C++ stdlib than
  its dependencies.
Add percona-server55

Closes #228.

Signed-off-by: Xiyue Deng <manphiz@gmail.com>
postgis15: mark as keg_only to avoid conflicts.
percona-server55: fix syntax.
percona-server55: fix formula name.
PostGIS 2.0.x Formula

Closes #260.

Signed-off-by: Xiyue Deng <manphiz@gmail.com>
Add Version 5.10.1 of vtk.

Closes #248.

Signed-off-by: Xiyue Deng <manphiz@gmail.com>
Merge branch 'master' of https://github.com/Homebrew/homebrew-versions
better keg message