Fix for GetBlockValue() after block 13,440,000

Forces the block reward to zero when right shift in GetBlockValue() is
undefined, after 64 reward halvings (block height 13,440,000).
Add new DNS seed from bitnodes.io.
[Qt] remove space from translation of client bitness

- its rather easy to leave out the space on Transifex, so remove it from
  the string
Fix importwallet nTimeFirstKey
Ignore temporary object files

Prior to this change, `git status` would report untracked files of the
following sort if run during a build:

    ?? src/rpcprotocol.o-e628def3

These files should be explicitly ignored not only because they are a
nuisance, but given that they appear and disappear quickly, they may be
inadvertently added to the index even if one has been careful to check
for untracked files with `git status` prior to a `git add .`.
RPC command getmininginfo showing right genproclimit
fix permissions in application bundle

Use INSTALL_DATA rather than INSTALL for copying non executable files in
OS X application bundle.

Tested by running "all appbundle" make target and trying the resulting
application bundle, host system is OS X 10.9.2 .
Make GetAvailableCredit run GetHash() only once per transaction.

This makes the first getbalance/getinfo 63x faster on my wallet.
Merge pull request #3922

c17f0a5 [Qt] remove space from translation of client bitness (Philip Kaufmann)
Merge pull request #3973

a60ab0b Make GetAvailableCredit run GetHash() only once per transaction. (Gregory Maxwell)
Add nHighTransactionFeeWarning as per #3969.
Fix `-printblocktree` output

PrintBlockTree output was broken starting from e010af70.
Everything appears on one line.

PrintWallet() added the newline after a block, but this functionality
was removed and no newline was added.

Seemingly, no one noticed. Add a newline after the block information
to fix this.
Merge pull request #3875

89d72f3 Add new DNS seed from bitnodes.io. (Addy Yeow)
Add Andreas Schildbach to gitian download scripts.
Remove weights from download config for now as it's unclear how it will be used in future.
Merge pull request #3907 from schildbach/gitian-downloader-aschildbach-key

Add Andreas Schildbach to gitian download scripts.
Merge pull request #3980

af4c2ac Fix `-printblocktree` output (Wladimir J. van der Laan)
Merge pull request #3950

76cee18 fix permissions in application bundle (Andrea D'Amore)
build: improve missing boost error reporting
doc: Add note about memory reqs for compilation