Fixed some typos in documentation

Change-Id: Ie674381ca9ec9fda5ebb21afc6cac8b4bc49fcd3
Added advanced color and opacity map controls

These controls are tables that display the scalar values and assigned
colors and opacities for the current color and opacity maps,
respectively. Colors and opacities are limited to the range [0, 1].
Colors are specified as RGB triplets. The first and last scalar values
cannot be modified through the table as these are set via different
controls.

In addition, tabular formatted text data can be pasted from the
clipboard using Ctrl-V. The tabular text data must be delimited with
an arbitrary amount of whitespace (no newlines allowed). Pasting
always begins from the upper left to the bottom right table cells.

Change-Id: I2c10c9306d7e98c45cc37cec2ac16683876182f9
Merge topic '14383-manual-tfer-function-control-points' into next

34412a6 Added advanced color and opacity map controls
c4a38ed Fixed some typos in documentation