docfix

stylize method names with ``code wrap`` and a light english revision.
remove duplicate sgr regexp expressions

was due to a merge conflict gone wrong ;/
remove dupe terms attar, we use getattr() instead
change \d{1,4} -> \d+, same meaning, >4
per EK; provide T.length() as a static method
brevity
fixes: T.cuf1 -> 1, T.cuf(2) -> 2

previously cuf1 and the like was unmatched.
\a\b\r\n are all terminal sequences, too.
commentfix
_horizontal_distance and _unprintable_length

just renames, a bit more about what they are for.
_sequence_padding was an awful name.
_unprintable_length is better than _sequence_length; "sequence" as a term might be confused such as iterables, etc., and single-byte terminal sequences such as "\b" aren't really a multi-byte sequence, are they? so would you call it a "sequence" or just simply a control character.?
more py2.6<->3.3 compat/agnostic
rename tests for _func_renames

sorry, should have gone with prior commit
new tests for T.length()