Readme anjana

See merge request eci/shinyscreen!22

Cosmetics

See merge request eci/shinyscreen!23

Extraction tab contains error input widgets that take error in the
+/-, so as the half-width of the interval centered on the value.

A new kind of control was produced that inlines the text of labels
with the input box. Another variant places two labels around the input
box (suitable for units).

Meaning of errors

See merge request eci/shinyscreen!21