GUI: fix sendcoinsdialog/sendcoinsentry
Merge pull request #3026 from sipa/checkunspend

Skip unspendable outputs in consistency check
internal miner: move 2 globals from main to miner

- moves 2 global variables from main.cpp/h to miner.cpp/h
- also removes 2 unneded includes in miner.cpp, that come from miner.h
  already
Removes obselete HomeBrew patches
Update Qt 4.8.3 download link
Merge pull request #3027 from cozz/cozz2

GUI: fix sendcoinsdialog/sendcoinsentry
Merge pull request #3031 from Diapolo/miner

internal miner: move 2 globals from main to miner
Merge pull request #3035 from fanquake/remove-homebrew-patches

Remove obselete HomeBrew patches
Merge pull request #3034 from fanquake/corect-qt-download-link

Update Qt 4.8.3 download link in Gitian Descriptors README
Import libsecp256k1
Support for libsecp256k1
gitian support for secp256k1 linux builds