Text usability

Here are the most pressing needs for text tool and dialog:

• (DONE) Make text editing on canvas not steal most shortcuts, so I can press ctrl-shift-t for the dialog when editing (but ctrl-shift-x works!)

• Implement esc, tab, ins in text tool (see KeyboardShortcutsToDo)

• (DONE) Enable Home, End in text objects

• (DONE) When clicking on a text object, the point must be located near to where you clicked, instead of always at the end of string

• Copy and paste of text must work when editing

• Eventually, implement selections (shift-arrows) and intra-line tspans for formatting text fragments

• (DONE) Even more eventually, implement text flow in a column or in an arbitrary shape (as external module?)

• (DONE) Oh yes, and text on a curve would be nice too

• In the dialog:

• • Divide into two tabs, one with the text editing field, the second (default) with everything else. Text editing within the dialog is not frequently needed, and the dialog will thus become less clumsy.

• • Make sure "font size" field reacts properly to arrow keys (now it's upside down)

• • (DONE) Fix https://sourceforge.net/tracker/index.php?func=detail