1. Make the build scripts pull by default, and remember the pull state in the build progress file (pulling is now just the first step of the build).
2. Allow a local prefs file at the root of the source tree to cause the scripts to not look in the prefs folder for a build prefs file.
3. Improve the input file parsing, to deal with trailing # as comments
4. Totally parse the checkout list file now before checking out, instead of parsing and checking out at line at a time.
5. Ensure that the build flag arrays and hashes are cleared out at the start of a build, so that mozilla-then-netscape builds don't get the union of the two sets of flags.
git-svn-id: svn://10.0.0.236/trunk@82212 18797224-902f-48f8-a5cc-f745e15eee43
