Bootphon/Wordseg: Wordseg-0.7

Added tools/wordseg-qsub.sh , a script to schedule a list of segmentation jobs to a cluster running Sun Grid Engine and the qsub scheduler. Added example phonological rules and updated contributong guide in documentation. In wordseg-prep ignore empty lines in both gold and segmented texts. In wordseg-syll the syllabification is improved: syllabification of words with no vowel, better error messages (see #35, #36). In wordseg-tp add of the mutual information dependancy measure. In the bash command, the argument --probability {forward,backward} is replaced by --dependency {ftp,btp,mi} (maintained for backward compatibility). See #40. In wordseg-ag : niteration is now 2000 by default (was 100), improved log of iterations with -vv , refactored postprocessing code: parallelized constant memory usage (was linear wrt niterations*nutts) tree to words conversion in C++ instead of Python temporary parses file is now gziped (gains a factor of 20 in disk usage) new --temdir option to specify another path for tempfile (default is /tmp) detection of incomplete parses (if any issues a warning) better comments in code, more unit tests