use windows exe from cygwin

1. add a dummy function

function adb {
    TOP=/cygdrive/c/Android/android-sdk
    "$TOP"/platform-tools/adb.exe "$@"
}

2. create a dummy symbol link
cd /usr/bin
mv gvim gvim.org

ln -s /cygdrive/c/Program\ Files\ \(x86\)/Vim/vim73/gvim.exe gvim