Remove whitespace before double colon in errors and logs

Remove unnecessary whitespaces in errors and log messages as previously discussed. E.g.
```
error("CAlert::CheckSignature() : verify signature failed");
```
The space before the colon (':') is removed.
This branch was created automatically with the following commands:
```
find . -type f -and \( -name \*.cpp -or -name \*.h \) -exec sed -i '' '/.*error(.*\".* : .*\"/ s# : #: #' {} \;
find . -type f -and \( -name \*.cpp -or -name \*.h \) -exec sed -i '' '/.*LogPrint(.*\".* : .*\"/ s# : #: #' {} \;
find . -type f -and \( -name \*.cpp -or -name \*.h \) -exec sed -i '' '/.*LogPrintf(.*\".* : .*\"/ s# : #: #' {} \;
```
on non GNU system (thus '' after -i, no \+ etc.). Developers are thus able to replicate its changes on their system to make rebase easy.

No manual changes in this branch so far. git diff --check empty.

This have to be handled later or before this PR to completely clean this up automatically (original lines from master):

1. src/qt/coincontroltreewidget.cpp - the above commands add a newline at the end of file. Do not ask me. why. sed was run on OS X 10.10.

2. These error messages are in the master already and look ugly and the above commands change them:

return error("AcceptToMemoryPool: : CheckTransaction failed");
return state.DoS(100, error("AcceptToMemoryPool: : coinbase as individual tx"),
return error("AcceptToMemoryPool: : nonstandard transaction input");

3. To keep things automatable, the following lines are touched as well.
LogPrintf("LoadBlockIndexDB(): transaction index %s\n", fTxIndex ? "enabled" : "disabled");
LogPrint("net", "got inv: %s  %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom->id);
LogPrint("net", "getblocks %d to %s limit %d from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop==uint256(0) ? "end" : hashStop.ToString(), nLimit, pfrom->id);
LogPrintf("AddToWallet %s  %s%s\n", wtxIn.GetHash().ToString(), (fInsertedNew ? "new" : ""), (fUpdated ? "update" : ""));

So a few questions/propositions:
1. git checkout -- src/qt/coincontroltreewidget.cpp or keep the added newline?
2. fix these error here manually or separate branch before this?
3. fix these four problematic lines manually in this branch (deleted whitespaces do not make effect anyway) or let them be?

I'd suggest also (manually) removing these double ``::``.