Move most of "ada/*" to the root directory (this makes sense, as this
repository has been dedicated to Libadalang for years), and rename
"ada/language" to "ada".
TN: T914-010
Followup on O519-029
This method makes it more convenient to reparse an anaylsis unit when we
already have a handle to this unit. Add it to the Ada, C and Pytho API
and update the related testcases to test it.
Change-Id: I24b1d54399f91bdfb050b404645f6c356ddfe98a
Revamp the analysis context primitives to create/remove analysis units
so that:
* their behavior is defined in error cases
* reparsing is possible
* parsing from a memory buffer is possible
Update existing testcases to cope with these changes and add new ones to
exercise these features in the C and Python APIs.
Followup on O519-029
Change-Id: I409d63bef32cb1a920f402d7957ba8cd2668eb66