Add timecop gem for time sensitive tests
Add typhoeus gem for easier http requests
Add Quarter value object to work with agency quarters #2

Contracts are grouped by quarters on most agency sites. The agencies
are required to publish a new list of contracts every quarter. For this
reason, I think it makes sense to scrape by quarter.
DFO scraper - incomplete #2
DFO scraper: Refactor. Use Mechanize and VCR

Use CSS selector hash to define selectors for a contract page
Use Mechanize instead of Typhoeus to request contract pages (better
control with Mechanize)
Use VCR for scraper tests that need to request an html page
ContractLoader: Move date extraction code in Contract model
DFOScraper: Refactor; Use Wombat gem; VCR for tests
Move tests for Contract::extract_dates
ContractLoader: Use ArgumentError instead of ContractLoaderError
DFOScraper: Small fixes
Scraper: Refactored scraper design #2

All scrapers now live in their own modules
Scrapers must inherit from ContractCrawler class and implement two
methods:
 `contract_urls` returns an array of urls that have the contract info
 `contract_hash(url)` reads the contract information from the given url
and returns the data as a Hash
Minor code cleanup
Contract: Add Contract::create_or_update
Use webmock instead of fakeweb in VCR
ContractLoader: Fix test
Reorganize Gemfile
Ability to limit the number of contracts scraped in a quarter #2
Add rake task to scrape contracts
Crawler for Parks Canada #4
rake contracts:scrape takes quarter as second param #5