Removed copyright and maintainer from Model.
Removes blank lines in print_error()
Adds blank lines in default message.
Ignores password file.

For now the encrypted password file will reside in the same directory
as the trove program. Will make this more modular in the future.
Refactors handle method to new name: initialize
Reads in encrypted data.

This commit adds the old csspw.py program to make use of some
functions therein. They will soon be merged into the Model and
generalized (e.g. use of GPG instead of bcrypt).

Controller reads now a file 'passwd.bfe' in initialize() that has
to be in the same directory with trove.py (file name and location
will change in the future). It asks for a master passphrase as needed
by bcrypt to decrypt the file and encrypt it again.
Adds search command to controller (and corresponding functions to model and view).

One can now search the list of entries decrypted by the program.
Still missing: if there is only one result after the search, one
should not be prompted to with a selection of one item, but it
should be shown immediately.
Further: when there is no help text available, the password should
be displayed at once.
Adds return values to all methods.
Adds doc strings to all Controller methods.
Adds doc strings to all Model methods.
Adds doc strings to all View methods.
Updates help text.

We will not use the SHA1 any more to identify the entry to edit/delete.
A standard search and selection menu will be used for that.
However, SHA1 will be used internally to make sure no one tampers with
the text file (this has not been done before in csspw). One could print
a warning if a calculated SHA1 does not match the stored value. This
might show the user that someone has worked on the decrypted file manually
(i.e. without trove).
Considers the case that a search returns only one result.

The entry is displayed at once. No selection menu is necessary
in this case.
Removes an error in controller when calling print_info().

Some lines were copied from the View class, and the reference to the
View was missing in the print_info() statements.
Prints entry description field only if not empty.
Shows full entry when no help text is stored.

When the mnemonic is not available the user is not prompted any
more to ask if the password should be displayed. The full entry
is shown immediately.
Changes internal data structure and drops csspw dependency.

This commit changes from a list to a dictionary as internal data structure to
store entries. The keys for the dictionary are the SHA1 hashes of the entry
objects. All remaining functions of csspw (that had been added as a module)
have been incorporated into the Model. The class that represents an entry is
called TroveEntry now instead of ListEntry.
Methods of Controller are ordered alphabetically.
Methods of View are ordered alphabetically
Simplification of search function (in Model and Controller).