Change since the last version CAIN

There was a version 2.09 but it is not considered here.

1. 2D differential luminosity added.
2. Lorentz transformation of lasers has been added.
3. Field-strength dependence of the anomalous magnetic moment of electron is taken into account in solving the Thomas-BMT equation  .
4. Polarization dependence of the beamstrahlung and the coherent pair creation has been included.
5. The kinematics in nonlinear QED subroutines was improved so as to accept non-relativistic electrons/positrons.
6. The final polarization of electron in the nonlinear Compton scattering was added.
7. Polarization change in linear and nonlinear QED, beamstrahlung and coherent pair creation processes when event generation is rejected is now taken into account.
8. Incoherent ee pair creation by Breit-Wheeler, Bethe-Heitler, and Landau-Lifshitz processes has been added.

1. Following pre-defined variables have been added:
   Kind, Gen
2. Following pre-defined functions have been added:
   M in, Max,
   A vrT, AvrX, AvrY, AvrS, SigT, SigX, SigY, SigS,
   A vrEn, AvrPx, AvrPy, AvrPs, SigEn, SigPx, SigPy, SigPs
   T estT, TestX, TestY, TestS, TestEn, TestPx, TestPy, TestPs
   L umEE, LumEEbin, LumEEH
3. Do-type sequence in PRINT/WRITE command became possible.
4. Maximum number of characters of user parameters is increased to 16. Also, the underscore `&#;'137' is allowed in parameter names.
5. The flags for beamstrahlung and coherent pair creation, which had been defined in the BBFIELD command, were moved to a new command CFQED (constant-field QED). This is more logical becuase CAIN computes these phenomenon due to the external fields, too. Acoording to this change, CFQED operand was added to CLEAR command. Except for this change, input data files prepared for CAIN can be used for CAIN.

1. There was a bug in CLEAR BEAM command when applied during a PUSH ENDPUSH loop. Fixed.
2. A bug was found in the file source/physics/bb/bbmain/bbkick.f in solving the equation of motion under the beam-beam force. It is a kind of double counting of the beam-beam effect. Fixed.
3. Several bugs were found in DRIFT, EXTERNAL command. Fixed.
4. There was a miss-spelled variable in subroutine EVUFN (in the directory
   source/control/deciph). (This has been overlooked because of missing
   IMPLICIT NONE.) Not very harmful. Fixed.
5. Total helicity luminosity was not calculated, although differential helicity luminosity was. (A bug in physics/lum/dlumcal.f) Fixed.
6. PRINT/WRITE command did not correctly understand the KIND operand. Fixed.
7. The polarization sign of the final positron in the subroutine for linear Breit-Wheeler process (source/physics/laser/nllsr/lnbwgn.f) was wrong. Corrected.