gdal 1.11.0

Bump stable version to [1.11.0, released on April 25th](http://trac.osgeo.org/gdal/wiki/Release/1.11.0-News).

* Add support for Google's LIBKML driver (didn't function right in last formula iteration). Requirement added to ensure HEAD or a release newer than current stable (1.2) is used, as it is [required by GDAL/OGR](http://www.gdal.org/ogr/drv_libkml.html). Quite a few improvements to the LIBKML driver, and its heavy use for kml and especially kmz access, warrant the extra bits added. Enabling driver remains optional.
* Add new external linking to libjson-c.
* Add SOSI format under unsupported.
* Now includes a pkgconfig, gdal.pc.
* Fix armadillo configure and test (probably broken for last 17 months).
* Add simple `(gdal|ogr)info --formats` test to verify third-party dylib loading; very useful when using complete or unsupported options, or when using plugins, like `gdal-grass`.

Tested with all options enabled on 10.7.5, installed to a non-standard prefix:

```
HOMEBREW_VERSION: 0.9.5
ORIGIN: https://github.com/Homebrew/homebrew.git
HEAD: baa46328a27a5bad52b27d2538aba2bb654dbe83
HOMEBREW_PREFIX: /usr/local/osgeo4mac
HOMEBREW_CELLAR: /usr/local/osgeo4mac/Cellar
CPU: 8-core 64-bit sandybridge
OS X: 10.7.5-x86_64
Xcode: 4.6.3
CLT: 4.6.0.0.1.1365549073
LLVM-GCC: build 2336
Clang: 4.2 build 425
X11: 2.6.5 => /usr/X11
System Ruby: 1.8.7-358
Perl: /usr/bin/perl
Python: /usr/local/osgeo4mac/bin/python => /usr/local/osgeo4mac/Cellar/python/2.7.6_1/Frameworks/Python.framework/Versions/2.7/bin/python2.7
Ruby: /usr/bin/ruby => /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby

```
Tested with `gdal-grass` formula.

Previous 1.10 version available, as keg-only, [here](https://github.com/OSGeo/homebrew-osgeo4mac/blob/master/Formula/gdal-110.rb).