- puts function definitions in a namespace ... {} rather than using namespace ...;
- remove trailing whitespace
- add trailing newline
- protect SQL statements from being formatted by clang-format
This eliminates the reliance on ThreadContext to provide GLObjectStore, and statically enforces that GL cleanup functions happen only when GLObjectStore::performCleanup is called.
With the elimination of the Map thread, this becomes important because there may be multiple GLObjectStore's per-thread, and Map will need to ensure that the correct context is active when calling GLObjectStore::performCleanup.
We're now reparsing tiles when they expire. We're also swapping out buckets atomically to avoid flickering data; i.e. we're displaying the old data as long as we don't have a new parsed bucket for that layer yet. The parsed buckets now live in the *TileData objects rather than in the TileWorker; only partially parsed == pending buckets will remain in the TileWorker. Once they're parsed, they're moved to the *TileData object.
This moves all texture updates and buffer uploads to the beginning of every frame, before we issue any drawing commands. This means the GPU typically has much more time to upload the data in the background until we actually need it, and doesn't have to pause to store/load the framebuffer.
