Implement advanced search querying

[Syntaf]

There is a current unfinished implementation under ImportDialog.receive(). This is connected to an observer which will call receive with a dictionary of parameter ranges that can be used to query the database. The function should find a list of objects matches all specified queries, where a '' field denotes that the user left this field blank. Objects should then be displayed to the screen just as the other functions do in ImportDialog

The dictionary params are:

key	value	format	desc
date	'0000-00-00'	year-month-day	The outer date of the time range
btime	'00-00-00'	hour-minute-second	Beginning time range (btime -> etime)
etime	'00-00-00'	hour-minute-second	Ending time range
blat	'0.0'	float	Beginning latitude range (blat -> elat)
elat	'0.0'	float	Ending latitude range
balt	'0.0'	float	Beginning altitude range (balt -> ealt)
ealt	'0.0'	float	Ending altitude range
plot	PLOTS	string	Type of plot ('backscattered' etc..)
ampm	'am'/'pm'	string	Whether the time range is AM or PM
file	'.....hdf'	string	File name

Use these to get a list of all objects that match the values of these keys (e.g. rng['date'])

[Syntaf]

There is a probable bug with 919f490 , in that the AM/PM specifier might need to be checked, and if yes add 43200 seconds onto get_sec (12 hours).

I don't have any files to test this bug with, so I'm just logging it for now before this issue can be finished. I'm guessing the search will fail if you have objects from a similar time range but separated by AM/PM only