CMessageHeader sanity changes

- Remove spurious `pchCommand[1] = 1` in CMessageHeader()
- Make sure that pchCommand is zero-padded if length is shorter than
  COMMAND_SIZE
- Use strnlen to determine length of pcmCommand in GetCommand
Add automatic script test generation, and actual checksig tests
Use a typedef for monetary values
update license of compat and crypto

- change license to be just MIT for all files in compat and crypto
- also add missing header end comments
- ensure default header include style
cleanup license and header end comment in chain.cpp/.h
Merge pull request #4960

8138cbe Add automatic script test generation, and actual checksig tests (Pieter Wuille)
Fix vector out of bounds in script tests
Merge pull request #5003

68af7d0 Fix vector out of bounds in script tests (Pieter Wuille)
Merge pull request #4990

7bec6dd cleanup license and header end comment in chain.cpp/.h (Philip Kaufmann)
0db65d8 update license of compat and crypto (Philip Kaufmann)
osx: fix signing to make Gatekeeper happy (again)

The approach from 65f3fa8d1 worked for signing on 10.9.4, but not newer
versions. 10.9.5 (and up) want each framework to stand alone.

Now in addition to copying the plist's from Qt for each framework, we put them
in per-version dirs and only symlink to the latest, rather than using symlinks
for any contents.
Fix formatting in  init.md
depends: update the comparison tool to a more recent version
Revert "travis: retry tests before giving up"

This reverts commit 7e3821c097c05a4790abac53ddd26ef28cb7cf4d.
tests: fix python test-runner for windows

Windows needed a few fixups to get the tests running:
1. bitcoin-tx needs a file extension in Windows. Take this opportunity to
   add an env file, which pulls variables out of our build config. This can
   be extended as needed, for now it's very simple.
2. After #1, split the args out of the exec key in the test data.
3. Correct the line-endings from windows stdout
tests: fix false-positive under win64

BN_ULONG isn't necessarily an unsigned long, as is the case on win64.
Merge pull request #5006 from TheBlueMatt/travis-new-comparisontool

depends: update the comparison tool to a more recent version
Update build-unix.md

Debian also need libboost-all-dev installed.
Merge pull request #5015 from theuni/win64test

tests: fix false-positive under win64
Merge pull request #5014

41d67c7 tests: fix python test-runner for windows (Cory Fields)
Merge pull request #5018

347a3a3 Update build-unix.md (JL2035)