adding prereqs for cygwin
Adds a line in the LCM makefile to modify the options passed to /usr/bin/install to ask for it to compare files instead of blindly replacing them.  This changes the LCM make install to not replace it's libraries when it installs, causing libbot to not recompile when nothing has changed.
Merge branch 'master' of https://github.com/RobotLocomotion/lcm-pod
adding gcc
adding wget as a prereq
ignore pod-build
adding xz to homebrew prereqs
Adds dependencies from a clean ubuntu install for LCM.