Support of the .pro file extension for Prolog.
Merge branch 'master' of https://github.com/github/linguist into pro
Improved the C++ heuristic for detecting based on included headers
Improved the Obj-C heuristic with a Regex matching multiple unique keywords

Also improved the C++ heuristic by checking for class without an @ on the front.
Added the end statements for the two new if statmeents

Did not know ends were required on one-liner ifs. Fixed.
Fixed the failing patten for detecting C++-only headers
More regex goodness to improve the detection of C++ vs C
Found out that nothing was ever getting returned from the heuristic function "find_by_heuristics", and that headers matching C, Obj-C and C++ were never getting checked heuristically
Fixed the C++ class matching regex that was breaking the test for C/jni_layer.h
Found my new heuristic was still not being used because heuristics had been switched off
Added two new heuristics tests for the new C/C++/Obj-C heuristics
Merge branch 'master' of github.com:DX-MON/linguist
Removed the matches variable from find_by_heuristics without re-breaking anything
Updated the samples database file as recommended
Add support for Cool

This change includes a brief (non-sensical) sample program I wrote to
illustrate many of Cool's language constructs, as well as a simple rule
to distinguish Cool files from Common Lisp or OpenCL (it has a line that
starts with the word 'class'). Further, it includes a second example
program adapted from an example contained in the Cool distribution
(list.cl), which contains a few further language constructs and captures
the style of a Cool program.
Ignore files related to Cocoapods.

These include Podfile, Podfile.lock, and Pods/.
Change unknown extension of PHP sample file
Try shebang detection if the extension is unknown
Refactoring of Language.detect
Update heuristics.rb

Added the iostream headers and std:: to the C++ heuristics. This covers issues 1250.