travis, build: further maven and gpg refinements

travis, build: fix mobile build issues on travis

travis: work around "timeout features"

* core, core/types: refactored tx chain id checking

Refactored explicit chain id checking in to the Sender deriviation method

* cmd/utils, params: define chain ids

mobile: initial wrappers for mobile support

Light client bugfixes and updates

Refactored explicit chain id checking in to the Sender deriviation method

EIP158 & 160 Hardfork

This commit implements EIP158 part 1, 2, 3 & 4

1. If an account is empty it's no longer written to the trie. An empty
  account is defined as (balance=0, nonce=0, storage=0, code=0).
2. Delete an empty account if it's touched
3. An empty account is redefined as either non-existent or empty.
4. Zero value calls and zero value suicides no longer consume the 25k
  reation costs.

params: moved core/config to params
Signed-off-by: Jeffrey Wilcke <jeffrey@ethereum.org>

Topic discovery bugfix

cmd: add swarm command line tools