Add more tests, for instance from unrtf

[pombredanne]

unrtf has several interesting RTF test files, some of which fail to open with pyth:
http://ftp.gnu.org/gnu/unrtf/?C=M;O=D
It could be a good addition to the test suite

[pombredanne]

From http://ftp.gnu.org/gnu/unrtf/unrtf-0.21.9.tar.gz , the following test files subset fail to open with pyth Rtf15Reader.read:

tests/EndNote.rtf
tests/chars.rtf
tests/body.rtf
tests/font_styles.rtf
tests/Greek1.rtf
tests/unicode4.rtf
tests/opensymbols.rtf
tests/emfpict.rtf
tests/Turkish.rtf