Added math.degrees, radians, and factorial

Added some trig function tests, too. There’s a Double-return-value
version of factorial to handle larger numbers, since Int64 tops out at
to factorial(20).
Merge pull request #9 from natecook1000/master

Added math.degrees, radians, and factorial
Merge pull request #10 from kareman/master

Defined internal variables and initialiser of _FileHandle_Generator as private
Now using access control (public/private) instead of old _private notation.
Using access modifier (private) instead of old prefix _private.
Added Pythonic-linter.swift. Did some minor cleanups picked up by linter.
Now running source checker on "make test".
Renamed linter to swift-style-checker.swift.
Improved documentation.
Using let instead of var where possible.
Typo.
s/lintFile/checkFile/
Now taking parameter timeout into account. Default 600 seconds.
Added re.sub.
Added re.match.
Visibility of re.matchedGroups should be private.
Added re.split.
Linked to swift-style-checker.swift
Added additional tests for re.split.
Added str.lstrip() and str.rstrip().