Support for Travis-ci (Continuous Integration Server)
Added travis-ci  build status to README
README improvements.
Update README.md

Removed use of odd syntax to refer to functions and be consistent.
Fix mavschema.xsd installation

Fix #204
Replace optparse with argparse: mavgen
Replace optparse with argparse: examples
Replace optparse with argparse: tools/magfit
Replace optparse with argparse: tools/AccelSearch
Replace optparse with argparse: tools/mavextract
Replace optparse with argparse: tools/mavgraph
Replace optparse with argparse: tools/mavflight mode & time
Replace optparse with argparse: tools/mavgps lag & lock
Replace optparse with argparse: tools/mavkml
Replace optparse with argparse: tools/mavlogdump
Replace optparse with argparse: tools/mavplayback
Replace optparse with argparse: tools/mavloss & sigloss
Replace optparse with argparse: tools/mavto gpx & mfile
Replace optparse with argparse: tools/mavsearch
Replace optparse with argparse: tools/mavmission