Bug 974803 - MWC Partners page: fix el, zh-TW

el: title overlapping with Firefox logo
zh-TW: text covered by Firefox’s tail in Marketplace section
cs, el, ja, pl, ro, sr: fix #explore arrow (cur or overlap)
Merge pull request #1726 from flodolo/bug974803_el_zhTW

Bug 974803 - MWC Partners page: improve display for locales