[CLEANUP] Add gitignores
[FIXUP] correct pipestatus location
[FIXUP] change default SAGE_BUILD_DIR
[FIXUP] make sage-env and basic startup not depend on the spkg directory
[FIXUP] sage-spkg: support local scripts
[FIXUP] new sage-build script
[FIXUP] copy csage, including headers
[FIXUP] correct path for docbuilder
[FIXUP] ntl: move libtool
[FIXUP] singular: move shared
[FIXUP] sagenb: install into site-packages
[FIXUP] remove mecurial
[FIXUP] correct doctests for the git layout
[FIXUP] remove SAGE_DATA
[FIXUP] correct values in sage/env.py
[FIXUP] Fetch upstream tarballs

TODO: find faster (portable) way to determine compression type
[FIXUP] gcc reference to spkg/installed
[FIXUP] make sage-coverageall respect new source location
[FIXUP] remove symlinks for sage library

this is no longer needed since we don't clone
the library into different directories anymore
[FIXUP] new upgrade system