Pycatsearch

Fixed wrong units appended to the values when copying/exporting the data with units.

Added movable parts of the interface to easily tune the window to everyone's needs. Now, the table of the results and the two upper sections can be resized, and the columns of the table can be in any order.

Urgent release to fix file dialogs not showing up.

Less important changes:
- fixed that ugly 99% progress at the end of downloading catalog data,
- refactored Preferences dialog to make it smaller,
- added icons from [`qtawesome`](https://github.com/spyder-ide/qtawesome) if it's installed,
- added an option to ignore a new version and not to warn about it.

Added _Check for Updates_ action in _Help_. With some luck, this will check for updates and install them if ones found.

The filling of the results' table became some 9 times faster.

Moreover, if the `orjson` package is available, it's used to load the catalog data instead of the built-in `json`. With `orjson`, the loading is almost twice faster. It's half a second benefit, but it's better than nothing.

Previously, all the PE files (`pycatsearch.exe`, `pycatsearch-async-downloader.exe`, `pycatsearch-downloader.exe`) were marked as GUI scripts, so no console output appeared. Now, `pycatsearch-async-downloader.exe` and `pycatsearch-downloader.exe` are non-GUI scripts, and `pycatsearch-cli.exe` added to show the output.

To search from a command line:
commandline
pycatsearch --min-frequency 118749 --max-frequency 118751 catalog.json.gz -n oxygen


To download catalog data:
commandline
pycatsearch-downloader --min-frequency 115000 --max-frequency 178000 catalog.json.gz

or
commandline
pycatsearch-async-downloader --min-frequency 115000 --max-frequency 178000 catalog.json.gz


To start the GUI:
commandline
pycatsearch

or
commandline
pycatsearch catalog.json.gz

to load `catalog.json.gz`.