Rename "Micro-Bitcoin" to "Zibcoin"

*  The lengthy word "microbitcoin" is abbreviated as "zibcoin" or just "zib".

*  The three letter code for zibcoin is "ZBC".

*  "Millibitcoin" is updated accordingly, to "kilozibcoin" or just "k zib", because multiples are more intuitive than fractions.
Merge pull request #1 from zibcoin/zibcoin-units

Rename "Micro-Bitcoin" to "Zibcoin"
Merge pull request #3 from zibcoin/zibcoin-master

Zibcoin master
Merge pull request #4 from zibcoin/0.8.2zib

0.8.2zib
Merge pull request #5 from zibcoin/0.8.3zib

0.8.3zib
Merge pull request #6 from zibcoin/0.8.4zib

0.8.4zib