Bumped version number to 0.19.0-SNAPSHOT
Added some more unit tests
Some more unit tests added
Updated note about non-stabilized API
Cleaned up some dead code
More unit tests
Completed unit tests for all expression nodes
More unit tests
Adds support for IfElse ternary operation functions.  These can be used in the compiler as well.  Much easier than adding basic parse support for ternary operands '?' & ':'.
Correct typo in getting_started.md
Correct some typos in expressions.md
Correct typo in numbers.md
Correct typo in bignumbers.md
Correct typo in command_line_interface.md
Merge pull request #149 from fcolas6013/patch-5

Correct typo in command_line_interface.md
Merge pull request #148 from fcolas6013/patch-4

Correct typo in bignumbers.md
Merge pull request #145 from fcolas6013/patch-1

Correct typo in getting_started.md
Merge pull request #146 from fcolas6013/patch-2

Correct some typos in expressions.md
Merge pull request #147 from fcolas6013/patch-3

Correct typo in numbers.md
Merge pull request #144 from mtraynham/if_else_function

Adds the ifElse function.