Update sqlhtml.py

Correcting some bootstrap3 icon classes
Fix debugger interaction due new DAL

Originally, __all__ was used to filter DAL and Field globals, but now the new module doesn't explicity set that attribute, so this filter was removed.
Note that using __dict__ as a replacement is not an option, as the new dal module exports a lot of common names like connection, base, etc.
Allow map_hyphen to work for application names

1. Handle hyphen -> underscore replacement of the app name early in map_app(), so the application can be identified and its routing rules used (if they exist).  Without this, the rewriter fails to find the application with the hyphen in place, and reverts to the default.

2. Disable underscore -> hyphen mapping of app name when creating static URLs, as they will be invalid paths
Update rewrite.py
fix cache clear with regex and tests
issue 2024: response.json sets by default content-type to application/json
set directly 'application/json' to avoid a call to contenttype
better assignment (tasks go to not running workers only). Thanks @PengfeiYu


- pep8 adjustments
- tasks were assigned to all ACTIVE workers... if a worker is busy processing a task, 
  there's no point on assigning tasks to it
fix issue 1931: preserve vars in grid search
fix issue 2029: response.stream bug with spaces in filename
new module appconfig.py
Merge pull request #558 from timnyborg/patch-1

Update sqlhtml.py
Merge pull request #559 from reingart/master

Fix debugger interaction due new DAL
Merge pull request #563 from ilvalle/fix-cache

fix cache clear with regex and tests
Merge pull request #564 from ilvalle/issue-2024

issue 2024 response.json sets default content-type to application/json
Merge pull request #565 from niphlod/scheduler/enhancement

better assignment (tasks go to not running workers only). Thanks @PengfeiYu
Merge pull request #569 from ilvalle/grid-search-fix

fix issue 1931: preserve vars in grid search
Merge pull request #570 from ilvalle/fix-stream

fix issue 2029: response.stream bug with spaces in filename
Merge pull request #571 from niphlod/contrib/appconfig

new module appconfig.py
class typo fix