Add basic PayPal module

Limitations for now:
* Only French-style (UUU,CC and not UUU.CC) balances; the choice is not left up to the user so
  it's hard to test
* No history (should be easy to add)

modules/paypal/browser.py

@@ -0,0 +1,71 @@
+# -*- coding: utf-8 -*-
+
+# Copyright(C) 2013      Laurent Bachelier
+#
+# This file is part of weboob.
+#
+# weboob is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# weboob is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with weboob. If not, see <http://www.gnu.org/licenses/>.
+
+
+from weboob.tools.browser import BaseBrowser, BrowserIncorrectPassword
+from .pages import LoginPage, AccountPage
+
+
+__all__ = ['Paypal']
+
+
+class Paypal(BaseBrowser):
+    DOMAIN = 'www.paypal.com'
+    PROTOCOL = 'https'
+    # CERTHASH = '74429081f489cb723a82171a94350913d42727053fc86cf5bf5c3d65d39ec449'
+    ENCODING = None  # refer to the HTML encoding
+    PAGES = {
+        '/cgi-bin/\?cmd=_login-run$':             LoginPage,
+        '/cgi-bin/\?cmd=_login-submit.+$':        LoginPage,  # wrong login
+        '/cgi-bin/webscr\?cmd=_account&nav=0.0$':  AccountPage,
+    }
+
+    def home(self):
+        self.location('https://' + self.DOMAIN + '/en/cgi-bin/?cmd=_login-run')
+
+    def is_logged(self):
+        # TODO Does not handle disconnect mid-session
+        return not self.is_on_page(LoginPage)
+
+    def login(self):
+        assert isinstance(self.username, basestring)
+        assert isinstance(self.password, basestring)
+
+        if not self.is_on_page(LoginPage):
+            self.location('https://' + self.DOMAIN + '/en/cgi-bin/?cmd=_login-run')
+
+        self.page.login(self.username, self.password)
+
+        if self.is_on_page(LoginPage):
+            raise BrowserIncorrectPassword()
+
+    def get_account(self, _id):
+        if _id != u"1":
+            return None
+
+        if not self.is_on_page(AccountPage):
+            self.location('/en/cgi-bin/webscr?cmd=_account&nav=0.0')
+
+        return self.page.get_account()
+
+    def get_history(self, account):
+        raise NotImplementedError()
+
+    def transfer(self, from_id, to_id, amount, reason=None):
+        raise NotImplementedError()