specify SHA1 thumbprint of desired code signing cert

eagerly tokenize when moving to position

This should fix errors when building the scope tree (as TokenIterators
are used when navigating the tokenized document).

Previously, it was possible that we would request the scope tree while
the background tokenizer was running (thereby encountering the document
in a half-tokenized state); the fix is to eagerly tokenize up to the
requested row so the TokenIterator never attempts to traverse a
non-tokenized document.

determine CRAN package availability with named list repos

bandaid for completion issue for '<-' with no surrounding spaces

Merge branch 'master' of github.com:rstudio/rstudio

prevent flickering when updating chunk toolbars

don't look for lower-case line endings value

fix missing '!' in CppTokenCursor method

fix missing '!' in CppTokenCursor method

use _WIN32 as windows define