adds a test for string literals
adds base TweakParser trait
removes some old pretty printing code
updates Readme.md with the travis badge
factors out Exp parsing code into a trait
factors out literal parsing code into a trait
factors out symbol parsing code into a trait
fixes travis badge
fixes capitalization in the travis badge
addes more swap files to .gitignore
adds result method, and removes string test for now

ResultW is a implicit value class that adds a result helper for unpacking simple, one expression parses, also having trouble parsing strings, will be pushed to later commits.
fixes a all compilation issues with new SymbolParser
factors out match parsing into MatchParser trait
fixes compilation errors with LiteralParser
factors out function parsing into FunctionParser trait
fixes compilation errors with ExpParser

adds self types for annotation sake
comments out unfinished features of the PrettyPrinter
fixes the ast to work with the new compilation process
updates the Parser to be composed of the new layers

factored out old code into separate traits to implement the "cake" pattern, so we can experiment with the parser with very little effort.
Merge branch 'cakefied-parser' of https://github.com/jroesch/Tweak into cakefied-parser

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