Bugfix: Crash when adding a new line at the top of the file, then pressing space and then a character.
Bugfix: Crash when adding a new line at the top of the file, then pressing space and then
a character.

This was caused by Input_isPositionWithinTextUnitInDirection() not checking if the result
of Text_closestPosInDirection() was null before passing pos to Text_analyseParagraph()

corinthia/corinthia-editor,corinthia/corinthia-editorlib,corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editorlib,corinthia/corinthia-editorlib,corinthia/corinthia-editor,corinthia/corinthia-editorlib,corinthia/corinthia-editorlib,corinthia/corinthia-editor