untis4j v1.2

Improvements✨:

• searchBy...(...) and findBy...(...) functions which take String as parameter ignore upper and lower case
• renamed klasse to class and klassen to classes
• better examples in README.md

Fixed bugs🐛:

• Different requested Session.getTimetable(...) returning now different results
• Session.reconnect() won't throw a ConnectionException anymore and replaces the old sessionId with the new one
• LatestImportTime.getLatestImportTime() returns long instead of a negative int

Other changes🛠:

• General code reformatting