[WIP] Fix #328 - Add check for trailing whitespace

[wilzbach]

I made the trailing whitespace inclusion at the lexer optin, s.t. you only pay for it when the trailing whitespace check is activated.
However, there's still no whitespace token stream.
Is libdparse popping them away?

For reference, it currently prints:

Include whitespace
typevoid line: 2
typeidentifier line: 2
type( line: 2
type) line: 2
type{ line: 2
type} line: 2
typevoid line: 5
typeidentifier line: 5
type( line: 5
type) line: 5
type{ line: 5
type} line: 5

[wilzbach]

Rebased.

[wilzbach]

However, there's still no whitespace token stream.
Is libdparse popping them away?

Yup, getTokensForParser overwrites its given LexerConfig:
dlang-community/libdparse#149

[ghost]

I'm doing a bit of cleanup and close this since it's been abandoned.