Merge pull request #64 from xeno-by/master

explicitly specifies the license for the scala.meta platform
Merge pull request #65 from xeno-by/master

reintroduces the Tree.$tag method to experiment with performance optimizations
Merge pull request #66 from xeno-by/master

also defines $tag in companions of ast classes
Merge pull request #67 from xeno-by/master

rolls back directory layout of the project to comply to the standard conventions
Merge pull request #68 from xeno-by/master

scala.meta.syntactic.ast => scala.meta.internal.ast
Makes scanner emit whitespace tokens
org.scalameta.syntactic.TypeString => org.scalameta.reflection.ClassName
moves Enquote and Escape to org.scalameta.show
normalizes whitespace tokens

no idea why there was a distinction between Tok.`\n` and Tok.LineFeed
implements robust prettyprinting for tokens

Tok.show[Code] now works and uses newly established Tok.code
to print exactly the string that corresponds to the token in source code.

Tok.show[Raw] now also works: shows offsets and properly escapes Tok.code
so that various flavors of whitespaces are printed in a friendly manner.

TokMetadata, synthesized by a helper macro, is now used to both provide
"expected $x, found $y" error messages and to do typetests on tokens.
fixes all dynamic tokens except for string interpolations
better stack traces for parser errors
Tok.toString now does show[Raw]

Otherwise it's really painful to debug the stuff
strategically inserts newlines where appropriate
a quickfix for the @token infastructure
some debug harness
this is what I missed when porting the old TokIterator!
finally fixes range positions for dynamic tokens
removes some debug printing
starts work on new interpolation tokens