[PATCH 0 of 2] highlight: avoid decode tracebacks

[Christian Ebert]

First patch replaces unnecessary keyword arguments.

Second patch tries to make a consistent approach at avoiding
tracebacks due to UnicodeDecodeError.

We need to pass encoding parameters to pygments lexers and
formatter.
To ensure that the lexer can digest its input, we encode the
input with util.tolocal.

Possible issue:
util._encoding and hgweb.encoding /conflict/.