Modifies deployment to ignore warnings -- in support of 'compile' with destructiveChanges.xml

If you maintain a destructiveChanges.xml over the lifetime of a project, you end up with things in there that may or not be deleted in your dev org. The default deployment option of ignoreWarnings=false causes deployment to fail if it tries to delete a component that's already deleted.

This patch sets ignoreWarnings=true on deployment. I honestly think we should set ignoreWarnings=True by default since, after all, they are warnings. But this is the conservative patch and leaves it in the hands of the MavensMateProject handler rather than setting it across the board. If you'd like me to update it, I'll gladly do so