moved files back a directory, and renamed them.
Huge set of changes (1433/1435 tests passing, L1-L3)

L2/Allocation: fixed bad in esp and spill location management.
L3/Linearize: fixed a small but bad off by 2 mistake in subtraction.
L2Interp.hs: fixed a bug where TailCall was prematurely whacking the top environment.
1l.cabal: removed lexec and x64, by merging them into lc. which now takes a -x flag to execute things natively.
LUnitTests: changed outputFileSearch to outputFileExt, because that makes way more sense.
NativeRunner.hs: removed runSCodeNative. callers just have to write the S file themselves now and call runSFileNative
L1L2MainAdjuster: now adjusting mains for L1 and L2 instead of just L1.
Compiler.hs: some light refactorings to make executing things natively make more sense.
CommandLine.hs: cleaned up some things, move some things out into the executables.
executables/Linterp: can now pass -t or --turtles flag to interpret all intermediate languages, all the way down.
executables/LC: can now pass -x or --exec flag to execute the final result natively.