Increased length of name field in alias tables and added a unique constraint.

The length of the name field in SpeciesAlias was increased to 50 characters
maximum and the name field in LocationAlias was increased to 100 characters
to account for compound names where the name is qualified by a region name
prefix.

Added a unique constraint on the name field in SpeciesAlias and LocationAlias
to ensure that more than one alias pointing to different entries in the
Species and Location tables is not possible.
Moved fixtures.py which contains the Factory classes up so other test cases can use them.
Added django-admin-enhancer to requirements.
Checklist include now defaults to False.

Setting Checklist include to False by default allows the include flag to be
omitted when loading data from CSV or JSON encoded files. Reloads of data
will not overwrite the existing value unless the field is explicitly included.
This makes it easier to manage sites such as eBird where data is available
for the past n days and is not grouped by Checklist. The data can be reloaded
multiple times and the database related fields (include, add_on, etc.) will
not be overwritten.
Replaced the flags field with a single boolean field, excerpt.

The flags field was originally used to generate different types of
report based on the status of an Entry, e.g X was used for exotic
species, R for rarities, etc. There were two values E which was
used to select a subset of entries to display for a checklist
and H which was used to display observations that were of particular
interest, e.g. scarce species or high counts, etc. Generally values
such a X and R were copies of thet Species status. These were copied
over as the Species status might change over time so a historical
record of which observations were considered rare would be useful to
maintain. However this is probably managed by a mehanism outside
of the database. In addition the distinction between excerpts and
highlights is not clear-cut. In the birdinglisboa project simply
displaying the most interesting observations from a checklist
provided the most interesting information to display. Hence the
flags fields and the two properties used to treat excerpt and
highlights as boolean properties are replaced by a single boolean
flag, excerpt, which can be used to select a given observation for
whatever reason.
Cleaned up localized strings and names used on the model.

The locale directory now contains a single reference language (English).
The locale for Portuguese (which was used in the original development)
was removed.
Fixed error when setting added_on date for new checklists.

The added_on field contains the date the checklist was added to the
database. When a checklist is saved the date was set when the id
is None. However this did not account for situations where the
added_on field was set - primarily used for testing. Now the
added_on field is only set when both it and id are None.
Added factories for LocationAlias and SpeciesAlias.
Removed unused commands.

validate_checklists is no longer required since a new Species will
be added to the database with a name_order of zero. When the checklist
is edited for publishing it cannot be save if any extry has a species
with a name_order of zero. This forces a check to see if the species
already exists with a similar name since the Species table should
already contains all the species in the world. For genuine new species
(in the event of a taxonomy change) the name_order can then be set
so the species appears in the correct position in the taxonomic order.

source_ebird is replaced by a scrapy spider from a sister project.
Updated tests to account for the removal of the flags field from Entry.

Also some PEP8 cleanup.
Refactored functions and management commands for loading data into the database.
Cleaned up actions and added tests.
Removed non-English localized fields. Fixed errors in search fields.
Added basic tests for model classes.