started the implementation of the 'db_updaters', the one's in charge of submitting all the information to database

the following aspects were changed or added:
. the 'uri_seeds' parameter in the 'db_updaters' initializers is transformed into a keyword parameter allowing more flexibility because the user can choose wether he/she passes it in the initializer or not
. created a 'set_uri_seeds' method allowing the user to add the uri seeds he/she wants
. added the necessary changes to take into account the maxcomp information i downloaded from the yahoo finance website
updated the related information of all the stock owners (enterprises) and mediators based on the data i have (only azteca, terra and maxcom)

in more details, the following tasks were performed:
. updated the sql script for the 'stock_owners' (enterprises) to the 3 i have right now
. updated the sql script for the 'mediators' from the information i have right now
performed a little preprocessing to the stock information extracted from the datasources in order to aid the db insertion process
created a whole new class hierarchy of 'db_adapters' to help the db insertion process and data mining
implemented the updating process for stocks comming from 'yahoo_finance' and changed some names in files and the django website to have 'maxcom' instead 'maxcomp' like i had

it's important to point the following things:
. the tests were very simple and i think more robust tests should be performed.
. the pair of columns 'date' and 'stock_owner_id' should be unique like some sort of PK because in that way there's no way to insert 2 actions for the same enterprise in the same date.
finished the implementation of the 'bd_updaters' and 'db_adapters'

some details must be taken into account:
. some preliminary test were performed in order test the correct behavior
. the db insertion is performed by pieces in order to avoid an excess of memory consumption.
performed a little more elabored tests for the 'db_updaters'

some aspects must be stressed:
. some tests assumed that the tables 'enterprises' and 'mediators' were empty.
. the insertion of new 'enterprises' and 'mediators' was also tested and it all worked well.
changed some of the data contained in 'terra13.csv' and 'maxcom.csv'

those changes were made to test if i was really inserting the correct data in db. as a matter of fact, i was correct but the data in 'terra13.csv' and 'maxcom.csv' are almost the same and that's why i got confused in the first place
finished the implementation of the query 'operative details'

it's important to stress the following aspects:
. like previous db interaction, this is also achieved by a sql query. i think that in a posterior version we should analyze wether to put it in db or not
. the only query implemented is this because i have no explanation for the other queries.
created a whole new hierarchy for the 'report_generators' and parformed some shallow tests

the following elements must be taken into account:
. the elements of the hierarchy are: 'abstract_report_generator', 'html_report_generator' and 'pdf_report_generator'
. right now the 'pdf_report_generator' can be left empy because it could be as simple as generating the equivalent html report and then converting it to .pdf