Some minor footer improvements

Removing copyrigt sign since we are not copyrighting things.

Changing hackmd.io to codimd.org since HackMD is more and more dividing
from CodiMD and may brings up wrong expectations.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

Author: SISheogorath

public/views/index/body.ejs

@@ -150,7 +150,7 @@
                         <option value="id">Bahasa Indonesia</option>
                     </select>
                     <p>
-                        &copy; 2018 <a href="https://hackmd.io">CodiMD</a> | <a href="<%- url %>/s/release-notes" target="_blank"><%= __('Releases') %></a><% if(privacyStatement) { %> | <a href="<%- url %>/s/privacy" target="_blank"><%= __('Privacy') %></a><% } %><% if(termsOfUse) { %> | <a href="<%- url %>/s/terms-of-use" target="_blank"><%= __('Terms of Use') %></a><% } %>
+                        Powered by <a href="https://codimd.org">CodiMD</a> | <a href="<%- url %>/s/release-notes" target="_blank"><%= __('Releases') %></a><% if(privacyStatement) { %> | <a href="<%- url %>/s/privacy" target="_blank"><%= __('Privacy') %></a><% } %><% if(termsOfUse) { %> | <a href="<%- url %>/s/terms-of-use" target="_blank"><%= __('Terms of Use') %></a><% } %>
                     </p>
                     <h6 class="social-foot">
                         <%- __('Follow us on %s and %s.', '<a href="https://github.com/hackmdio/CodiMD" target="_blank"><i class="fa fa-github"></i> GitHub</a>, <a href="https://riot.im/app/#/room/#codimd:matrix.org" target="_blank"><i class="fa fa-comments"></i> Riot</a>', '<a href="https://translate.codimd.org" target="_blank"><i class="fa fa-globe"></i> POEditor</a>') %>