Fix Backspace and Delete characters

Backspace key must generate the backspace character (\010) and
Delete key must generate the delete character (\0177). In
some systems the kernel configuration for erasing previous character
is \0177, so some programs (for example cat, ed, mail, ...), can not
understand the correct meaning of backspace. In this cases it is only
needed this command:

	stty erase 
Increment XSync consistency

This patch cleans up a style inconsistency.
Removing two unnecessary gettimeofday().
Merge remote-tracking branch 'origin/master' into omaster
fix cursor handling when alt screen is disabled

I don't like this alt screen thing, but when
allowaltscreen == 0, the cursor is still saved
and restored after calling 'less' (or 'man').

This patch makes allowaltscreen == 0 usable.
typedefs instead of #defines

Replaced #defines with typedefs where possible, patch attached.