Add ability to specify fiat amount when sending bitcoin.
check to see if fiat button already exists on send tab before telling user they must restart Electrum to see it
check if fiat button exists on send tab before updating its caption with the newly selected fiat currency
Merge pull request #1 from dpdtex/temp1

Bug Fixes
better handling of very small fiat numbers and mBTC
Merge pull request #2 from dpdtex/temp1

better handling of very small fiat numbers and mBTC
fixed issue when exchange rate not available (eg, no connection)
Merge pull request #3 from dpdtex/temp1

fixed issue when exchange rate not available (eg, no connection)
wrapped strings with  _("string text") to enable language translation
Merge pull request #4 from dpdtex/temp3

wrapped strings with  _("string text") to enable language translation
Merge pull request #623 from dpdtex/master

Add ability to specify fiat amount when sending bitcoin