envsetup.sh: Fix the `reposync` function

It seems ionice can't find `repo` if it's in ~/bin, even if ~/bin
is in the user's $PATH.  Placing repo into /usr/bin or /usr/local/
bin works, but is undesirable (build instructions from both AOSP
and CM tell users to put repo into ~/bin, and repo likes to update
itself from time to time).

This forces the reposync function to use the full path to the repo
binary.

Change-Id: I9dc4a3d4ec3f39563e3a84de7321189700079c2e
build: Add "aospremote" command

 * Adds the git remote for the matching AOSP repository.

Change-Id: Iad03fb95874ff39a39083218aec0d834e82b4480
mka: change how make is called

in some environments make -j N xxx results in compiling target 'N' instead of 'xxx'
make -jN xxx will always make 'xxx' with N number of threads
Signed-off-by: Arnav Gupta <championswimmer@gmail.com>

Change-Id: I77f17c9286a5ef1d61163d8f978900fb4c24e2e7
cout: move to $out

Change-Id: I3b5bf8a5f62dcdf267662bb97a2073150152cfa6
build: Add cafremote command to envsetup

 * So lazy!

Change-Id: I99a988180abb4fb486d4ebbb842bb9eda03bf1bc
envsetup: Fix remote functions to deal with symlinks

Change-Id: I6f35dc30dda22149b2c37e1c6c7d41ea7239d3bb
envsetup: drop unnecesary exports

export -f is a bashism and we don't actually need it, so lets remove it.

Change-Id: I9228cef0c4a9543b3d34fdc39a368ad0238431e2