_read_tle fails to handle bstar values that start with + character

[movermeyer]

_read_tle fails to handle bstar and mean_motion_sec_derivative values that start with + character.

Sometimes, these values starts with a '+'.

Example (from ISS):
1 25544U 98067A 15235.81765006 +.00009573 +00000-0 +14486-3 0 9999
2 25544 051.6452 106.3529 0001648 090.4174 004.9123 15.55401685958567

The + character is a valid character in this position, as indicated by Celestrak

"Columns with a '+' can have either a plus sign, a minus sign, or a space and columns with a '-' can have either a plus or minus sign (if the rest of the field is not blank)."

[mraspaud]

Thanks for reporting this, but as you mentioned in the other thread, it was fixed in the develop branch.