Revert "Litecoin: Remove native coin generation."

This reverts commit 94bf538131a5eb5c837044b14789a29981b7e0e6.

Conflicts:
	src/init.cpp
Litecoin: s/BitcoinMiner/LitecoinMiner/ and detect scrypt implementation
RPC: add getbestblockhash, to return tip of best chain
Pass check level, check depth to VerifyDB()
RPC: add 'verifychain', to verify chain database at runtime