enhance translation possibilities in TransactionDesc / misc other changes

- remove "#include <QString>" as this is included in the header
- add some missing plural forms that can be translated
- change "yours" into "own address", which is easier to understand and translate in that context
- cleanup translatable strings to not include HTML or unneeded chars (e.g. ":")
- resize TransactionDescDialog a little (remove unwanted line-breaks with non english translations)
Add a timer to check for changes in immature or unconfirmed balances,
when these are non-zero. Fixed a minor mem leak.
GUI: merge sign/verify message into a single window with tabbed UI

- add UI-feedback via QValidatedLineEdit
- copy button for generated signature was moved to the signature output field
- add an addressbook button to verify message tab
- input fields are now evenly ordered for sign and verify tabs
- update FIRST_CLASS_MESSAGING support to ensure a good UX
- add a button and context menu entry in addressbook for verify message (to be consistent with sign message)
- focus is now only set/changed, when clearing input fields or adding an address via addressbook
- re-work / update some strings
- ensure model gets initialized in the SignVerifyMessageDialog constructor
- add checks for a valid model to both addressbook buttons
- remove unneeded includes for Qt GUI elements that are listed in ui_signverifymessagedialog.h anyway
update QRCodeDialog

- remove unused #include <QDebug> and lblBTC label
- update Bitcoin input field to a BitcoinAmountField to allow Bitcoin unit selection
- use BitcoinUnits::format for the resulting amount parameter in the generated URI (always use BTC as per BIP21)
- move MAX_URI_LENGTH and EXPORT_IMAGE_SIZE to guiconstants.h
- add OptionsModel in AddressBookPage and use it in on_showQRCode_clicked() to pass it to QRCodeDialog
- add OptionsModel in QRCodeDialog to enable display unit updates
- add updateDisplayUnit() slot to be able to imediately update currently set bitcoin unit
- make all labels in the UI-file plain text
- resize dialog to match for an updated layout (fields are now stacked and new field)
- remove unused parameters from private slots
- only enable save button, when QR Code was generated
- show message when entered amound is invalid
- add read-only QPlainTextEdit field to output generated URI
Merge pull request #1559 from sje397/BalanceSignalFix

Add a timer to check for changes in immature or unconfirmed balances,
Merge pull request #1552 from Diapolo/txdesc

GUI: enhance translation possibilities in TransactionDesc / misc other changes
Merge pull request #1518 from Diapolo/qrcodedialog

update QRCodeDialog
Merge pull request #1469 from Diapolo/signverifymessagedialog

GUI: merge sign/verify message into a single window with tabbed UI
Fix OBO in socks5 auth proposal. This fixes compatibility with openssh's socks5 proxy and tor's .2.3.x branch.
Merge pull request #1565 from jrmithdobbs/socks5-fix

Fix OBO in socks5 auth proposal.
fix typo in optionsmodel.cpp
Merge pull request #1566 from Diapolo/typo

fix typo in optionsmodel.cpp
Compact serialization for variable-length integers
Compact serialization for variable-length integers: tests
Add CCoins: pruned list of transaction outputs
Compact serialization for scripts
Compact serialization for amounts
Compact serialization for amounts: tests
Add CTxUndo: transaction undo information
One file per block