PHA routines

```
 int ReadPHAtypeI(char *filename, long PHAnumber, struct PHA *phastruct)
```
Read the type I SPECTRUM extension from a FITS file - if there are multiple SPECTRUM extensions then read the one with EXTVER=PHAnumber.
```
 int ReadPHAtypeII(char *filename, long PHAnumber, long NumberSpectra,
                   long *SpectrumNumber, struct PHA **phastructs)
```
Read the type II SPECTRUM extension from a FITS file - if there are multiple SPECTRUM extensions then read the one with EXTVER=PHAnumber. Within the SPECTRUM extension reads the spectra listed in the SpectrumNumber vector.
```
 int WritePHAtypeI(char *filename, struct PHA *phastruct)
```
Write the spectrum to a type I SPECTRUM extension in a FITS file.

 int WritePHAtypeII(char *filename, long NumberSpectra, 
                    struct PHA **phastructs)

Write the multiple spectra to a type II SPECTRUM extension in a FITS file.

```
 int ReturnPHAtype(char *filename, long PHAnumber)
```
Return the type of the SPECTRUM extension with EXTVER=PHAnumber.

 void DisplayPHAtypeI(struct PHA *phastruct)

Write information about the spectrum to stdout.

 void DisplayPHAtypeII(long NumberSpectra, struct PHA **phastructs)

Write information about multiple spectra to stdout.

 int RebinPHA(struct PHA *phastruct, struct BinFactors *bin)

Rebin spectrum.

```
 int CheckPHAcounts(char *filename, long PHAnumber)
```
Return 0 if COUNTS column exists and is integer or COUNTS column does not exist.
```
 long ReturnNumberofSpectra(char *filename, long PHAnumber)
```
Return the number of spectra in the type II SPECTRUM extension which has EXTVER equal to PHAnumber.