Fixed a crash in the LLL parser (when you input non-ascii characters); minor GUI tweak.

The crash happens when you input any sort of non-ascii characters, e.g. the Italian accented letter ò.
Using boost::spirit::standard instead of boost::spirit::ascii seems to prevent the crash.
This way, characters seem to be treated as UTF8 when compiled.
E.g.:
* "pero" -> PUSH32 0x70 0x65 0x72 0x6f
* "però" -> PUSH32 0x70 0x65 0x72 0xc3 0xb2

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Improved the GUI a little, to prevent the text widgets from scrolling down all the way when visualizing blocks, pending transactions or contract info.