Added missing themes for ggplot2 graphs

[Vitalis95]

Fixes #9332

@rdstern @N-thony , added theme_excel and theme_excel_new for excel themes, theme_solarized_2for the Solarized palette, theme_economist_white which approximates the style of the 'Economist' and theme Settings Functions; theme_update, theme_replace, theme_get, theme_test and reset_theme_settings

[rdstern]

@Vitalis95 very nice, and seems to work.

I tried the 4 new themes, and also like the reser_theme_settings. I wasn't sure however, what replace, get, update and test are supposed to do. They don't seem to do any harm, but don't they need something more added? Maybe using them is ready for a tweak to the script?

Then I found a bug - not from here, because I trhink it has been there a time. If tricky to fix, I'll approve, and this can be a new issue. If using the boxplot in the Climatic > Check Data > Boxplot, then it doesn't work with facets. I tried with the zambia Eastern data, where there are 5 stations. In the dialog the facets are not set properly. Facets is disabled, which is fine, but Station should be set there, to avoid the bug.

[rdstern]

@Vitalis95 thanks.
@N-thony over to you. A simple but really nice improvement.