Fix signedness issue reading scripts (resolves issue 478)
Wallet template: couple of misc tweaks
TransactionBroadcast: refactor
WalletTool: allow skipping of mandatory extensions.

This allows it to read MultiBit wallets.
Add a builder function to InventoryMessage
Request 11 peers by default in wallet-template
Tweak broadcast logic again.

 Now broadcast to half the connected peers immediately, and wait until half of the rest (i.e. a quarter) have announced the tx. This should give some robustness against a random subset of peers silently swallowing transactions.
Merge branch 'master' into litecoinj

Conflicts:
	core/src/main/java/com/google/litecoin/core/TransactionBroadcast.java
	core/src/test/java/com/google/litecoin/core/TestWithPeerGroup.java