Server error on mammo export - suspect missing data as per Issue #28

[Ed McDonagh]

Reported by DJ Platten. Looks like it might be the same as Issue #28 that was fixed for RDSR imports, but not applied to mammography or Philips CT.

[Ed McDonagh]

Added 'if not then = none' statements for all the filtering fields to avoid crashes on export. Addresses #43.

→ <<cset 74b572c39d5e>>

[Ed McDonagh]

Added 'if not then = none' statement for performing physician name to cater for fluoroscopy exports. Addresses #43.

→ <<cset 8606513e802c>>

[Ed McDonagh]

Added 'if not then = none' statements for the Philips CT import routine. Addresses #43. Now needs testing.

→ <<cset 93ee81a4fcb7>>

[Ed McDonagh]

Correcting a number of alignment issues introduced by commit 74b572c39d5ef. References #43.

→ <<cset 4a9f6063337d>>

[Ed McDonagh]

Previous commit addressing #43 fixed issues for all but Hologic study. This commit adds if statement for collimated_field_area before calculating area - value doesn't exist in Hologic and was therefore falling over on import. Addresses #43.

→ <<cset 6426a885fbb9>>

[Ed McDonagh]

Initial changes to import code tested with 0.3.8-b1 - all but Hologic now work.

Import code changed again to cater for missing collimated field area in Hologic images and tested with 0.3.8-b2. All the tested mammo imports now work, and modified import code still works with Senographe DS images.

[Ed McDonagh]

Addresses #48. CT xlsx export now works with patient age criteria. Also improved filtering to only filter on fields that have a value. This would probably have been a better way to fix previous export errors - see #28 and #43. TODO apply new technique to csv CT, fluoro and mammo exports -- see #49 -- and add age filters to fluoro and mammo.

→ <<cset 540245ffe427>>

[Ed McDonagh]

Fixes #48 and #49. Patient age filtering and exporting now works. Exports are now more robust rendering the modifications made for refs #28 and #43 unnecessary. Filtering before exporting is now unnecessary - see #50 for docs changes required.

→ <<cset bf88368dd533>>