rework help messages for fee-related options

- mention the units and show the default for -paytxfee
change "char pch[200000]" to "new char[200000]"
[Qt] don't allow translation of our example btc address
Issue warning if collecting RandSeed data failed
Relax IsStandard rules for pay-to-script-hash transactions

Relax the AreInputsStandard() tests for P2SH transactions --
allow any Script in a P2SH transaction to be relayed/mined,
as long as it has 15 or fewer signature operations.

Rationale: https://gist.github.com/gavinandresen/88be40c141bc67acb247

I don't have an easy way to test this, but the code changes are
straightforward and I've updated the AreInputsStandard unit tests.
[Qt] New status bar Unit Display Control and related changes.

- New status bar control shows the current Unit of Display.
  When clicked (left,or right button) it shows a context menu
  that allows the user to switch the current Unit of Display (BTC, mBTC, uBTC)
- Recent Requests and Transaction Table headers are now updated when
  unit of display is changed, because their "Amount" column now displays the
  current unit of display.
- Takes care of issue #3970 Units in transaction export csv file.
- Small refactors for reusability.
- Demo Video https://www.youtube.com/watch?v=wwcr0Yh68go&list=UUG3jF2hgofmLWP0tRPisQAQ
- changes after Diapolo's feedback. Have not been able to build after last pool, issues with boost on MacOSX, will test on Ubuntu these changes.
- removed return statement on switch
- renamed onDisplayUnitsChanged(int) to updateDisplayUnit(int)
- now getAmountColumnTitle(int unit) takes a simple unit parameter. moved to BitcoinUnits.
Remove timing-based signature cache unit test

Two changes:

First removes a unit test that fails in my development environment
(OSX, compiled -g3 with clang).

sipa says that's not terribly surprising; the CMutableTransaction change
makes signing a little more expensive but verification quicker. The unit
test timed sign+verify-uncached versus verify-cached-five-times.

He also says the test will be invalid when libsec256kp1 is integrated
(because validation is super-optimized over signing).

core.h change fixes a compiler warning (clang -Wall : CMutableTransaction defined
as struct, declared as class in script.h).
ensure clean and consistent "namespace" usage

- remove some missplaced ;
- ensure end of a namespace is clearly visible
- use same formatting when using namespace
small cleanup of #ifdefs in BindListenPort()

- SO_NOSIGPIPE isn't available on WIN32 so merge the 2 non-WIN32 blocks
- use predefined names from header for IPV6_PROTECTION_LEVEL and
  PROTECTION_LEVEL_UNRESTRICTED
add missing BOOST_FOREACH indentation in ThreadSocketHandler()
add OpenSSL RAND_cleanup() on OpenSSL shutdown

- to securely erase the memory used by the PNRG
- also rework 2 comments in OpenSSL init
update coding.md to reflect changes by pull

- also mention alphabetical include ordering
JSON-RPC method: prioritisetransaction <txid> <priority delta> <priority tx fee>

Accepts the transaction into mined blocks at a higher (or lower) priority
Allocate more space if necessary in RandSeedAddPerfMon

Currently we use a fixed buffer of 250000 bytes to request
HKEY_PERFORMANCE_DATA. In many cases this is not enough, causing the
entropy collection to be skipped.

Use a loop that grows the buffer as specified in the RegQueryValueEx
documentation:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms724911%28v=vs.85%29.aspx

(as the size of the performance data can differ for every call, the
normal solution of requesting the size then allocating that can't work)
Merge pull request #4414

a90689f Remove timing-based signature cache unit test (Gavin Andresen)
Merge pull request #1583

2a72d45 JSON-RPC method: prioritisetransaction <txid> <priority delta> <priority tx fee> (Luke Dashjr)
Add an option to allow users to disable relaying/mining data carrier transactions
Simplify build instructions
Merge pull request #4392

8ae973c Allocate more space if necessary in RandSeedAddPerfMon (Wladimir J. van der Laan)
be873f6 Issue warning if collecting RandSeed data failed (Wladimir J. van der Laan)
fcb0a1b change "char pch[200000]" to "new char[200000]" (daniel)
Merge pull request #3715

e44fea5 Add an option to allow users to disable relaying/mining data carrier transactions (Luke Dashjr)