Properly close files
If a fileobject is specified, it is the callers responsibility to close the fileobj.
Bug fix: parse_file() properly raise exception.
Previously, the exception was created, but not raised nor returned.
Add test function to check for closed file.
Bug fix: WorldFolder.iter_chunks() returns Chunk subclass
Update changelog for 1.4
Add historic changelog info for 0.6-0.9
Fix Travis-CI testing.
Update path to libz.so to 64-bit architecture now used by Travis.
Move from PIL to Pillow (PIL fork with Python 3 support).
Fixed a bug that sometimes made write chunks in the region file header.

parse_header() now updates the file size before parsing the header
making possible to call it after modifiying the region file.

Now the header is updated everytime the region file is modified.
Merge pull request #67 from Fenixin/fix

Fixed a bug that sometimes made write chunks in the region file header.
Merge remote-tracking branch 'twoolie/master'
Add Travis testing for Python 3.3
Recommend Pillow instead of PIL library
Minor fix: allow trailing slash in folder names.
Support for Python 3 for map.py
Fix file-closed test for Python 2.6
Update documentation.
Some notes about region files.
These should be checked for potential bugs.
Convert constants to class variables
Add errorcode for overlapping chunks
Potential bug fix: free sector always calculated.
It was not calculated for chunks with unknown error codes