Remove modelines

Removed modelines are better than modelines that differ from file to
file.
Configure travis to use prebuilt dependencies

Dependencies are now hosted in a github repository and this brings two advantages:

- Improved build time with travis since we no longer have to build each
  dependency
- Less chance of build errors due to external servers being down since Github is
  now the single point of failure
Handle special KE_EVENT case where maxlen < 3

Possible bug reported by @oni-link [here](https://github.com/neovim/neovim/pull/485/files#r11664573).

It was handled by doing a circular walk through a key buffer and saving the
index between calls with a static variable.

Also replaced some `char_u` occurrences by `uint8_t` and removed unused
headers in input.c module.
Remove 'textmode' option

'textmode' is an option obsoleted for at least 10 years in favor of
'fileformat'.
vim-patch:7.4.245

Problem:    Crash for "vim -u NONE -N  -c '&&'".
Solution:   Check for the pattern to be NULL. (Dominique Pelle)

https://code.google.com/p/vim/source/detail?r=80421d934ebde183ce545ab8d9eb3a4c2065c169