Split OdfUtils.isCharacterElement into
OdfUtils.isCharacterElement which only
checks for character elements (space, tab,
line-break) and OdfUtils.isAnchoredAsCharacterElement,
which reflects the fact that it checks for elements
which are 'as-char' (the way frames can be anchored),
in that they have the same kind of surrounding
positions' walkability as any character element
like spaces or tabs.

* Fix wrong documentation for this method.

* Update tests to reflect this, and also test
annotations and annotation wrappers.

* Update the other places in the codebase
to use the correct one of the two methods.