- ability to set the WHERE condition (allow editing the SQL query)
- Scale factors
- Abort running pdf preview generation when we search for something new
- Index .ebup
- Preview for: .txt, source code files, .ebup, images
- Stats: Number of results found
- PdfPreview: Files per file, or directory (so basically filter the 
results)
- PdfPreview: Remove arbitrary limit of 300 
- Hide PdfPreview Tab if there are no pdfs in the results
-Tagging: add an "addtag" utility, to assign tags to folder and files
-gui: Search expclitly for tags, list by tags, remove tags, add tags
-gui: Filter already found results. For example, "show only folders",
or just search with those results.
-split each tab into own class, not everything in mainwindow.cpp?
Menu:
-Delete from index
-Delete from fs
-Reindex
Filter:
contains: (default, implicit)
type:d 
type:file
endswith:
startswith:
mtime:
tag:
page:
SearchWorker::setFilters()