Jsc/exponent numerals

[juansc]

The scanner recognizes numbers in scientific notation. As of this change, numbers are considered to be floats if

• There is a decimal in the fractional part or the exponent (1.3, 3.4E12,123E4.56)
• If the exponent is raised to a negative power, since this implies moving the decimal point to the left (100E-1 means 100 becomes 10.0)

[rachelriv]

LGTM