Pass open token to MustacheNode for flag parsing
Push Source helper method
Lookahead control classes
Define test cases
Kill unused functions
Use accept for all compiler traversal
Fix whitespace
Add strip token parsing to lexer
Wrap AST nodes in strip opcodes if defined
Load strip flags from lex stream
Defer content output

Allows for stripping of the content after the fact.
Implement strip opcode
Use ~ rather than () for whitespace control.