bashrc: open new terminals in same directory
emacs: move android-mode keys to "C-c C-a" prefix

the default "C-c C-c" conflicted with various git/magit modes (like when
editing a commit message).
emacs: manually set company-backends

use the default as a starting point, but remove some backends which
cause problems. basically instead of trying to be smart with semantic or
clang, which often don't work at all, just use dabbrev-code which is
consistently okay.
emacs: properly disable tab as yasnippet trigger

two different types of tab needed unbound. hopefully this is it now