added support for proxy environment variables
Adjusts chunk sizes for larger files
Fix for file locking bug, thread 1992629
Update to 4.0. Added in bugfixes from Appupdater codebase.
made this an importable module
uncommented stuff i commented out for testing
Added command line version of the editor, meditor.py
Fixed runaway memory when checking a checksum
bugfixes for download resuming
Enabled gzip encoding for non-segmented downloads