Merge branch 'refactor-heuristics' into 1036-local

* refactor-heuristics: (43 commits)
  update docs
  Clean up heuristic logic
  Allow disambiguate to return an Array
  Rename .create to .disambiguate
  docs
  Remove inactive heuristics
  Refactor heuristics
  Not going back
  docs
  Move call method into existing Classifier class
  Try strategies until one language is returned
  Remove unneded empty blob check
  Add F# and GLSL samples.  Add Forth and GLSL extension .fs. Add heuristic to disambiguate between F#, Forth, and GLSL.
  byebug requires ruby 2.0
  Remove test for removed extension
  Fix typo in test
  add rake interpreter
  add python3 interpreter
  Remove old wrong_shebang.rb sample
  Add byebug
  ...

Conflicts:
	lib/linguist/heuristics.rb
	test/test_heuristics.rb

lib/linguist/languages.yml

@@ -558,6 +558,8 @@ Crystal:
   - .cr
   ace_mode: ruby
   tm_scope: source.ruby
+  interpreters:
+  - crystal
 
 Cucumber:
   extensions:
@@ -735,6 +737,8 @@ Erlang:
   - .es
   - .escript
   - .hrl
+  interpreters:
+  - escript
 
 F#:
   type: programming
@@ -814,6 +818,7 @@ Forth:
   - .for
   - .forth
   - .frt
+  - .fs
 
 Frege:
   type: programming
@@ -867,6 +872,7 @@ GLSL:
   - .fp
   - .frag
   - .frg
+  - .fs
   - .fshader
   - .geo
   - .geom
@@ -930,6 +936,8 @@ Gnuplot:
   - .gnuplot
   - .plot
   - .plt
+  interpreters:
+  - gnuplot
 
 Go:
   type: programming
@@ -1195,6 +1203,8 @@ Ioke:
   color: "#078193"
   extensions:
   - .ik
+  interpreters:
+  - ioke
 
 Isabelle:
   type: programming
@@ -1702,6 +1712,8 @@ Nu:
   filenames:
   - Nukefile
   tm_scope: source.scheme
+  interpreters:
+  - nush
 
 NumPy:
   group: Python
@@ -1888,6 +1900,8 @@ Parrot Assembly:
   - pasm
   extensions:
   - .pasm
+  interpreters:
+  - parrot
   tm_scope: none
 
 Parrot Internal Representation:
@@ -1898,6 +1912,8 @@ Parrot Internal Representation:
   - pir
   extensions:
   - .pir
+  interpreters:
+  - parrot
 
 Pascal:
   type: programming
@@ -1940,6 +1956,8 @@ Perl6:
   - .p6m
   - .pl6
   - .pm6
+  interpreters:
+  - perl6
   tm_scope: none
 
 PigLatin:
@@ -2004,6 +2022,8 @@ Prolog:
   - .ecl
   - .pro
   - .prolog
+  interpreters:
+  - swipl
 
 Propeller Spin:
   type: programming
@@ -2067,6 +2087,8 @@ Python:
   - wscript
   interpreters:
   - python
+  - python2
+  - python3
 
 Python traceback:
   type: data
@@ -2087,6 +2109,8 @@ QMake:
   extensions:
   - .pro
   - .pri
+  interpreters:
+  - qmake
 
 R:
   type: programming
@@ -2241,6 +2265,8 @@ Ruby:
   - .watchr
   interpreters:
   - ruby
+  - macruby
+  - rake
   filenames:
   - .pryrc
   - Appraisals
@@ -2327,6 +2353,8 @@ Scala:
   - .scala
   - .sbt
   - .sc
+  interpreters:
+  - scala
 
 Scaml:
   group: HTML