recent: improve name of button 'Expand' 'Collapse'

Currently the buttons to expand/collapse all items on the list is simply
named as Expand/Collapse, it is quite(?) ambiguous in English and much
more ambiguous if the translator directly translates it(ex.展開/折疊)
without patching the 'all' meaning on it(ex.全部展開／全部折疊）
Simply patch the source language should be a good idea.

Signed-off-by: Ｖ字龍(Vdragon) <pika1021@gmail.com>
Makefile: generate pot under po/ instead

If there's no reason to put pot under root dir we should overwrite the
orignal pot file.

Signed-off-by: Ｖ字龍(Vdragon) <pika1021@gmail.com>
widgets: fix msgmerge warnings

Just to make msgmerge happy, though.
It would also slightly make the strings translator-friendly.
I'm not familiar with Python so it may require some review and
codingstyle tune.
Signed-off-by: Ｖ字龍(Vdragon) <pika1021@gmail.com>
browse: let parenthesis to be translatable

Move the parenthesis into the gettext string and let the translator
determine the correct one.
For example, double-width parenthesis "（）" instead of ones in ASCII are
used in zh_TW locale.

Signed-off-by: Ｖ字龍(Vdragon) <pika1021@gmail.com>
Merge pull request #271 from Vdragon/improve_source_language

browse: make parenthesis to translatable

Signed-off-by: David Aguilar <davvid@gmail.com>
Merge pull request #267 from Vdragon/fix_recent_button

recent: improve name of 'Expand' and 'Collapse' buttons

Signed-off-by: David Aguilar <davvid@gmail.com>
Merge pull request #268 from Vdragon/fix_makefile_build_pot_path

Makefile: generate pot under po/

Signed-off-by: David Aguilar <davvid@gmail.com>
Merge pull request #270 from Vdragon/fix_gettext_warning

widgets: fix msgmerge warnings

Signed-off-by: David Aguilar <davvid@gmail.com>