Qalculate! version 0.6.2 released

Qalculate! version 0.6.2 has been released with some urgent bug fixes and a number of feature enhancements.

Changelog:

- Fix segfault on exit
- Force use of -O2 instead of -Os
- Fix a^b^c = a^(b^c) not (a^b)^c
- Fix rounding and precision in display of numbers
- if(), function, error, warning, load, save and title functions were not activated (oops!)
- Fix parsing of default value of text argument
- Fix display of empty vector
- Fix import of CSV file to matrix
- Fix E in rpn mode
- Fix rad unit being dropped in unsolved sin/cos function
- Fix ! (NOT)
- Change -5^2 = (-5)^2 to = -(5^2)
- Variable edit fixes
- Display also the parsed and formatted expression in history window
- GUI for subfunctions
- GUI to show numbers in base between 2 and 36
- Alternative to use lower case letters in numbers
- Alternative to round halfway numbers to even in display
- Alternative disable complex and infinite results
- Ability set number base for whole expression and enter epxressions in base functions
- Export to CSV file
- Fetching exchange rates message and slightly changed behaviour
- Undefined, implicit unknowns disabled by default
- Make symlink from qalculate-gtk to qalculate
- Documentation updates
- ...