Fix MOSH_ESCAPE_KEY validation

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
mosh-client: Catch all exceptions when ensuring client is shut down

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Do multiple-line scrolls as a single move
termemu: respect $SHELL and exec argv if given
make termemu work with no arguments again
make Terminal::Cell work with std::<vector> as the container for UTF-8 characters
fix reverse scroll bug
fix iterators invalidated by insert/erase on std::deque
glorious git craptitude
change some operator[] to method at()
make termemu work with no arguments, take 2
use std::deque for Terminal::Framebuffer::rows_type
first try at COW on rows (still broken)
tr1-ify and comment
Small C++11 syntax correction
Fix bugs in COW rows and scrolling and cursor positioning.  Now seems to work correctly
Fix compile error.  Fix cursor positioning bugs.  Add dumb scroll for whole display.
Don't do anything in put_row() if new and old row are the same object
bring back to C++03 + TR1
Only create one blank row where multiple rows are needed