Merge x/exp/shiny/font to x/image/font.

 example/font/main.go                  | 105 +++++++
 font/font.go                          | 204 +++++++++++++
 font/plan9font/example_test.go        |  93 ++++++
 font/plan9font/plan9font.go           | 556 ++++++++++++++++++++++++++++++++++
 font/testdata/fixed/7x13.0000         | Bin 0 -> 3136 bytes
 font/testdata/fixed/7x13.0100         | Bin 0 -> 3908 bytes
 font/testdata/fixed/7x13.0200         | Bin 0 -> 3095 bytes
 font/testdata/fixed/7x13.0300         | Bin 0 -> 2631 bytes
 font/testdata/fixed/7x13.0400         | Bin 0 -> 3623 bytes
 font/testdata/fixed/7x13.0500         | Bin 0 -> 2492 bytes
 font/testdata/fixed/7x13.0E00         | Bin 0 -> 1235 bytes
 font/testdata/fixed/7x13.1000         | Bin 0 -> 2354 bytes
 font/testdata/fixed/7x13.1600         | Bin 0 -> 1825 bytes
 font/testdata/fixed/7x13.1E00         | Bin 0 -> 3713 bytes
 font/testdata/fixed/7x13.1F00         | Bin 0 -> 3012 bytes
 font/testdata/fixed/7x13.2000         | Bin 0 -> 2310 bytes
 font/testdata/fixed/7x13.2100         | Bin 0 -> 3206 bytes
 font/testdata/fixed/7x13.2200         | Bin 0 -> 3532 bytes
 font/testdata/fixed/7x13.2300         | Bin 0 -> 1613 bytes
 font/testdata/fixed/7x13.2400         | Bin 0 -> 1013 bytes
 font/testdata/fixed/7x13.2500         | Bin 0 -> 2747 bytes
 font/testdata/fixed/7x13.2600         | Bin 0 -> 1765 bytes
 font/testdata/fixed/7x13.2700         | Bin 0 -> 1762 bytes
 font/testdata/fixed/7x13.2800         | Bin 0 -> 1918 bytes
 font/testdata/fixed/7x13.2A00         | Bin 0 -> 620 bytes
 font/testdata/fixed/7x13.3000         | Bin 0 -> 569 bytes
 font/testdata/fixed/7x13.FB00         | Bin 0 -> 912 bytes
 font/testdata/fixed/7x13.FE00         | Bin 0 -> 387 bytes
 font/testdata/fixed/7x13.FF00         | Bin 0 -> 1687 bytes
 font/testdata/fixed/README            |   9 +
 font/testdata/fixed/unicode.7x13.font |  68 +++++
 31 files changed, 1035 insertions(+)