pointofsale: generated bitcoin url might contain invalid characters

The bitcoin invoice url generated for the QR code might contain illegal
characters because the labels can have any text. In default it already
contains spaces (ie. the naming convention "Invoice - 0001").

The invalid URL did confuse e.g. the Bitcoin Wallet Android app, that
couldn't read bitcoin addresses from the generated QR code.

This is fixed by escaping the label text before displaying it as a
QR code.
Merge pull request #462 from imrehg/posfix

pointofsale: generated bitcoin url might contain invalid characters
Fix: hide tray icon on close
Merge pull request #467 from thgh/trayfix

Fix: hide tray icon on close
Fix for resetting options to default on program start when in portable mode.
Merge pull request #471 from Zomnut/master

Fix for resetting options to default on program start when in portable mode
Remove trailing whitespace.
Parse amounts from CSV with Decimal and not float.

This fixes a bug where amounts are read from a CSV file incorrectly due to
floating point representation error. For example, the string 0.009 will be
parsed as 0.00899999, and then converted to 899999, resulting in one fewer
satoshi being sent as part of the transaction generated from the CSV file.
Merge pull request #476 from shunyata/bugfix/parsing-error-in-csv-transaction

Bugfix/parsing error in csv transaction
added getversion command
Merge pull request #483 from flatfly/patch-2

added getversion command
fix for getversion 

i had pasted the wrong definition, sorry
Merge pull request #484 from flatfly/patch-1

fix for getversion
abort export privkeys if wallet has no seed
Set initial 'running' attribute in Network class

This was causing a AttributeError when network.is_running() was called before the network was started.
Merge pull request #491 from Jud/master

Fix error when network.is_running() is called before the network is started.