Revert "Merge pull request #15 from lembacon/master"

Some problems found in those commits:

1. there is uneven line spacing between (vertically aligned) candidates
in the switcher (seen in some of the many pages in the menu).

2. the vertical position of the first candidate is not stable as the
input changes; with color scheme 'aqua' or 'ink', an additional pixel in
a color slightly different from highlighted background color appear from
time to time.

3. improved candidate spacing won't replace the trailing whitespaces
in balancing the spaces before candidates and making candidate texts
vertically centered to our eyes.

This reverts commit 118b9999ea02fe7fd43267553e256203d4aa8854, reversing
changes made to b4178817defd7c7f00f238cf4d8f1138602ef64d.