Bump charlock to 0.7.3

This version includes a fix for the encoding lookup table for some
encoding aliases in the ICU detection API
add the fixture
.ston extension for "Smalltalk Object Notation"

See https://github.com/svenvc/ston
"looks like I should have used JSON lexer

- let's see what travis has to say
send to travis
ahhh, caps are sorted before lower case ...
add sample files
Merge branch 'ston_test' of github.com:dalehenrich/linguist into ston_test
Merge pull request #1260 from dalehenrich/patch-1

.ston extension for "Smalltalk Object Notation"
Samples
Merge pull request #1259 from github/bump-charlock-again

Bump charlock to 0.7.3
Add F# sample.  Add Forth extension .fs.
Update samples.json.