Column sorting improvements

[iz-sai]

• Customize sort direction indicator: it used to be something like △, probably we can add it as a user setting in the main configuration function of AstroTools in the HTML header?
• Can we probably make some special data-type to sort strings considering them to be astronomical object names? For instance, in such sorting mode "King 8" should come before "King 13" because it's more natural to have strings with same prefix sorted arithmetically by the id afterwards. I may recall it wrong, but in samp-webtools we used to have such sort type because it was explicitly requested by researchers.

[AnotherOneAckap]

Added new option for sort icon and new column data type 'astronomical-object-name'

[iz-sai]

Confirm, everything works. Could you please only leave a check for remaining sorting indicators on other fields? At http://ocl.sai.msu.ru/catalog webpage default sort indicator is returned inside HTML by the webserver, so when user clicks to sort by another column, the original one above α2000 remains there (and if you click on this column heading there will be 2 indicators on it).

[iz-sai]

Another thing to add is column sorting with "value ± error" content. It used to work in the samp-webtools, but now your code does it wrongly with numeric sort for some reason.

[AnotherOneAckap]

Now it tries to parse float in cell, which means longest symbol sequence from string begining which looks like number will be used as sort value, or -Infinity on parsing fail.

[AnotherOneAckap]

Is it all about this issue?