#155 Minor typos in math and in y-error bars - fix provided

[Edward Sternin]

These are known to the administrator, but others might want to try before the code is updated.

Counting length of array is off by one (Thanks, GAH)

src/bltVecMath.c
307c307
<         count = 1;
---
>         count = 0;

y-error bar generation has 3 typos on two lines (note the - to + change as well):

src/bltGrLine2.c
3743c3743
<                 yHigh = elemPtr->x.values[p->index] - 
---
>                 yHigh = elemPtr->y.values[p->index] + 
3787c3787
<                 yLow = elemPtr->x.values[p->index] - 
---
>                 yLow = elemPtr->y.values[p->index] -