ExVCR.Filter.filter_request_header

[smeevil]

Added a new function to filter the request headers of cassettes: ExVCR.Filter.filter_request_header
Added test for hackney, ibrowse and httpc.
Updated Readme to explain usage.

Example config:

config :exvcr, [
  vcr_cassette_library_dir: "test/fixture/vcr_cassettes",
  custom_cassette_library_dir: "test/fixture/custom_cassettes",
  filter_sensitive_data: [
    [pattern: "<PASSWORD>.+</PASSWORD>", placeholder: "PASSWORD_PLACEHOLDER"]
  ],
  filter_request_headers: ["X-Algolia-API-Key", "X-Algolia-Application-Id"],
  filter_url_params: false,
  response_headers_blacklist: []
]

Or to just remove a header when using a cassette:

use_cassette "index/add" do
  ExVCR.Config.filter_request_headers("X-Algolia-API-Key")
  {:ok, "my_test_id", 1395699332} = AlgoliaSearch.Index.add(@index, "my_test_id", "foo", "moo")    end

This would also close #69

Let me know if this solution is ok :)

[coveralls]

Coverage decreased (-0.1%) to 93.412% when pulling 4ae7a08 on smeevil:master into 25c3c82 on parroty:master.

[parroty]

Great, thanks!

[smeevil]

My pleasure, thanks for the great library and the very quick merge / release !